Generally, buildings such as gymnasiums, halls, and classrooms have concrete floors, so that an additional floor has to be installed, and when a floor is installed, a variety of conditions such as flatness of the floor, superior walking performance according to buffering and shock-absorbing functions against a concrete floor, and sound-insulating and vibration-isolating functions for minimizing noise are required to be sufficiently considered. Although a variety of installation methods may be considered to install a floor above an indoor concrete floor of conventional buildings such as gymnasiums, halls, and classrooms, the following method is representatively used. Various layers of PE films are laid above a concrete floor to prevent humidity, and then an AS felt is applied above the laid PE films. Here, the AS felt may be omitted as necessary. Supporting posts are vertically arranged above the AS felt, and, above the supporting posts, plastic wedges of which fine tooth-shaped unevennesses are formed in an inclined manner are disposed on the corresponding oblique side of each block which is separately formed so as to adjust the height of a floor from the unlevel concrete floor. After that, the floor is installed through a series of installing processes comprising arranging sleepers above the plastic wedges so that the sleepers and the supporting posts are orthogonally disposed each other, arranging vibration-isolating rubbers above the sleepers in a proper interval, arranging joists above the vibration-isolating rubbers so that the joists and the sleepers cross each other, and sequentially disposing water-proof plywood and flooring boards above the joists.
However, according to a conventional structure for installing a floor, an installation period is lengthened and material as well as labor costs rise because members and installing processes required to install the floor are increased, thereby causing bad effects to a floor assembly installation, work efficiency, and economic efficiency. In addition, each member has to be used without omission in order to install a floor, and the height of the floor becomes higher than that of a concrete floor by at least 120 mm (millimeters) because each member has a determined thickness by considering shock applied to the floor or strength and durability of the floor, so that the floor is inevitably caused to be thicker, thereby causing problems in which a long-term strength stability is remarkably reduced or noise is made by an echo phenomenon after installation.
In addition, according to a conventional structure for installing a floor, a vibration-isolating rubber is interposed between a sleeper and a joist in an exposed state, so that vibration-isolating and shock-absorbing effects against vibration and shock applied from a floor are inevitably offset as time passes, and although the vibration-isolating rubber has a certain degree of hardness, in case of a gymnasium floor required to absorb a strong vibration or shock, the vibration-isolating rubber may be dented or be broken at the center when a strong shock is applied for a long time, so that the vibration-isolating rubber has remarkable structural problems in which an exhibition of the function becomes difficult or considerably lost.
A conventional method for installing a floor uses a recycled chip below a receiving space of any chosen one between a lower water-proof plywood and a lower water-proof plywood piece, wherein the recycled chip is broken or split and totally loses an elastic effect, and a connection section of the support mounted onto the recycled chip is broken or split as time passes, so that the floor is split. A conventional method for installing a floor uses a recycled chip below the support, and has a problem in which a broken section of the floor may not be repaired or the floor may not be recycled when the recycled chip is used.
A conventional method for installing a floor is the non-environmentally friendly one which uses a large amount of woods because a wooden floor frame for the fundament is used, is greatly harmful to a human body because a preservative is used, and has a problem in which the installed floor is twisted or deformed when undried woods are used.